Purple martins have proven to be very beneficial to the health and comfort of humans because their main diet consists of mosquitos and other insects that bite people and cause itching. Such insects also may carry diseases such as malaria and yellow fever. A single purple martin can devour as many as 2,000 mosquitos and other insects each day and therefore they are much desired in areas where mosquitoes are prevalent. Purple martins, however, are very selective about their living quaffers since they have a social instinct and like to dwell near others of their same species. This instinct is conspiciously lacking in most other birds. Also, purple martins will not nest in dwellings which are not scrupulously clean, nor will they nest in dwellings which other birds such as sparrows or starlings have occupied.
Many efforts have been made to provide birdhouses for various types of birds including purple martins in which some means has been provided for cleaning the houses after the young have been reared and left the nest. Some of these devices have been mounted on relatively tall posts to reduce the possibility of predators attacking the birds.
A variety of gourd-shaped nesting arrays have been suggested in the prior art, including arrays which may be lowered from a normally raised position for cleaning, observation and the like. Thus, Patliff, U.S. Pat. No. 3,783,831 (incorporated by reference) discloses the use of gourds for purple martin nesting arrays and teaches the use of gourd-like shapes for purple martin nesting. As disclosed at Column 3, lines 60 et. seq. "one or more houses can be mounted on a particular post equipped with appropriate cross members." Similarly, Wiener, U.S. Pat. No. 3,792,685 (incorporated by reference) discloses a purple martin birdhouse which is slidably mounted on a post to facilitate raising and lowering of the birdhouse for cleaning and/or observation.
The birdhouse assemblies of the present invention present radial arms supported on a central sleeve which is slidably mounted on a pole and raised and lowered by a winch and pulley. According to a preferred embodiment, uncontrolled rotation of the central sleeve about the pole during windy conditions may be controlled. Such uncontrolled rotation may not be disadvantageous in assemblies used for other purposes such as clothes drying as disclosed by Redding, U.S. Pat. No. 66,520 and Schater, U.S. Pat. No. 198,049. Nonetheless, such rotation is undesired in a birdhouse assembly and may even make the assembly uninhabitable.
Accordingly, the present invention provides a birdhouse assembly that is particularly adapted for housing purple martins. The assembly permits the housing of these birds by means of an array that is particularly attractive to the birds, which prevents or discourages predators of the birds and which may be cleaned or observed easily. Such assembly is, furthermore, according to a preferred embodiment quite stable in an outdoor environment and is not susceptible to undesired rotation around its mounting pole when the wind blows which could discourage purple martin nesting.